Frames for decorative art, mirrors, posters and like may be formed from a plurality (usually four) of sides, or frame parts, which are joined to each other at mitered ends. These frame parts are often made from stock which is relatively narrow. Such narrow frame parts have exhibited tendencies in the past to flex or bow when subjected to a heavy force, or the mitered frame joints may pull apart. For example, if a planar sheet of glass is disposed between the frame and the underlying artwork, and the frame is hung by hanging means attached to the back of the top frame part, the weight of the glass and frame can cause the top frame part to bow undesirably. Such lateral movement of the frame parts is observed notwithstanding a tightly joined miter at each corner; that is, the bowing may occur solely due to the tendency of the narrow frame part to bend under stress.
Such bowing has been observed in narrow frame parts made from metal, composites such as plastics, and wood.
In addition, it has been observed that the frame joints may open and even come apart when subjected to heavy stress.
To overcome these problems, frames of the prior art have been manufactured with straps of plastic, wire or cardboard to prevent the sides from pulling apart, as shown in FIG. 1. This arrangement may not, however, prevent the sides from flexing inwardly. Also, it is not effective in preventing the mitered joints from separating slightly.
Another prior art method is shown in FIG. 2, where wire is threaded through screw eyes located on each side of the frame and pulled together with the ends twisted together. This has similar problems.
In addition, with frames comprised of an inner frame (strainer) and an outer frame, nails can be inserted on all four sides to join the inner and outer frames.
The above described prior art methods of providing strength to frames are expensive to manufacture and often do not provide the desired effectiveness.
It is thus desirable to provide to a frame made from narrow frame parts means to prevent undesirable lateral movement of the frame parts or separation of the mitered joints.
It is further desired to provide such means which are inexpensive, simple to implement, and can be utilized with various sized and shaped frames already in use by the consumer.